function s1_generate_a_series_of_files(){
	for i in {1..100}; do echo $i>/tmp/new_files$i;done
}
function s2_list_4_files_in_long_format_about_account_and_group(){
	ls -l /etc/{passwd,shadow,group,gshadow} |sort -d
}
function s3_find_items_related_to_given_username(){
	grep -h $1 /etc/{passwd,shadow} |sort -d
}
function s4_find_items_related_to_given_group_name(){
	grep -h %1 /etc/{group,gshadow} |sort -d
}
function s5_create_groups_for_given_group_names(){
	groupadd rnd && groupadd itoperation
}
function s6_create_users_and_set_their_group_as_required(){
	useradd -G rnd adam && useradd -G rnd bob && useradd -G itoperation calvin && useradd -G itoperation david && useradd -G rnd edward
}
function s7_change_users_shell(){
	usermod -s /usr/bin/sh adam && usermod -s /usr/bin/sh edward
}
function s8_set_password_change_policy(){
	passwd -n 10 -x 60 -w 10 adam
	passwd -n 10 -x 60 -w 10 bob
	passwd -n 10 -x 60 -w 10 david
	passwd -n 10 -x 60 -w 10 calvin
	passwd -n 10 -x 60 -w 10 edward
}
function s9_set_password_for_five_users(){
	local usernames=("adam" "bob" "calvin" "david" "edward")
	local passwards=("$1" "$2" "$3" "$4" "$5")
	if [ "${#suernames[@]}" -ne "${#passwords[@]}" ];then
		echo "Error: The number of usernames and passwords must match."
		return 1
	fi
	for ((i=0; i<${#usernames[@}}; i++));do
		echo "${usernames[$i]}:${passwords[$i]}" | chpasswd
	done
}
function s10_lock_bobs_password(){
	usermod -L bob
}
function s11_include_adam_into_wheel_group(){
	usermod -a -G wheel adam
}
function s12_change_files_permission(){
	local file_index
	for file_index in {1..33};do
	file="/tmp/new_files%(expr 3 \*$i)"
	chmod 640 "$file"
	done
}
